This is an extension of gfm_strikethrough.txt. Some of these tests are also pulled from commonmark-hs.

Two tildes

Basic strikethrough is between two tildes:

~~This is *stricken out*~~

<p><del>This is <em>stricken out</em></del></p>

Backslash escapes:

~~This is \~\~stricken~~

<p><del>This is ~~stricken</del></p>

Intraword strikeout:

This~~is~~stricken

<p>This<del>is</del>stricken</p>

~~This~~is~~stricken~~

<p><del>This</del>is<del>stricken</del></p>

Punctuation is ignored for purposes of determining flankingness on two tildes:

Here I strike out an exclamation point~~!~~.

<p>Here I strike out an exclamation point<del>!</del>.</p>

One tilde

One tilde—and this is where we differ from commonmark-hs—is allowed in certain situations:

~This is stricken out~

<p><del>This is stricken out</del></p>

Backslash escapes:

~This is \~stricken~

<p><del>This is ~stricken</del></p>

Intraword strikeout requires two tildes:

This~is~nothing

<p>This~is~nothing</p>

~This~is~nothing~

<p><del>This~is~nothing</del></p>

Punctuation is used for purposes of determining flankingness:

Here I fail to strike out an exclamation point~!~.

<p>Here I fail to strike out an exclamation point~!~.</p>

Tilde runs can't mix.

Here I fail to strike out a tilde ~~~.

<p>Here I fail to strike out a tilde ~~~.</p>

Here I fail to match up ~~tildes~.

<p>Here I fail to match up ~~tildes~.</p>

Here I fail to match up ~tildes~~.

<p>Here I fail to match up ~tildes~~.</p>

Double tildes are allowed to contain single tildes, and the other way around:

~~This ~is stricken.~~

<p><del>This ~is stricken.</del></p>

~This ~~is stricken.~

<p><del>This ~~is stricken.</del></p>

The first one wins.

~This ~~is stricken~ but this is not~~

<p><del>This ~~is stricken</del> but this is not~~</p>